Welding AMC 20 rear-end

[Swoop]

I've been told that the AMC20 is a good rear-end as long as you truss the top of the rear-end for strength & weld the tubes. What size plate would you use to truss the top of the rear-end? Would 1/4 inch plate be good? Does the truss have to go all the way or would I stop it at the U-bolts. Another words does the truss need to go to the end of the rear-end and the U-bolts be knoched out? Do I need to weld the entire thing, or can I put like 2 inch welds down it? and What type of weld would I use stick or MIG? Can the tubes be spot welded? (like in 4 spots) or do they need to be welded all the way around? Does the rear-end need to be disassembled or can I just drain the oil out? Thanks for any info.

 

[81CJ5baller]

Great questions. I need the same info. Does anyone have a diagram of what this would look like? That would be awesome!

 

[Purple77CJ7]

I trussed my AMC20 with some 3/8 x 3" flat that I had. I ran from just beside the u-bolts across the top of diff to the other side. I used three pieces. One on each axle tube and the third across the top of the diff joining the other two pieces. It is welded to the tubes and the diff housing.I stitch welded and switched side to side so I didn't build up to much heat in one spot. I ended up with it welded solid. I also welded were the axle tubes fit into the diff. I used a stick welder, and I think 7014 rod. I did all this with the axle installed under the jeep, with all the guts and oil in it. Just take your time so you don't build up to much heat. It would be a lot easyer to weld it up with the axle out from under the Jeep. 1/4" flat would probably work.

 

[Old Dog]

I just did a google search for AMC20 truss and found all kinds of pic's and ideas. Might try that.
I think 1/4" might not be heavy enough for the truss but thats just me.
Also I would weld the tubes all the way around
IMO both are needed so you don't bend or twist a tube like I did. (I did both)

 

[Swoop]

Cool that is what I needed to no. I have some 3/8 plate ill stitch weld the truss and welded the tubes complete. I guess if I take my time I will not have to Disassemble The Rear end, but Isn't there a seal where I have to weld the tube to the chunk

 

[PaRenegade]

Here is my plan. This is just the template and still needs some tweaking. I might flatten off the top and he cut the AMC insignia's backwards, plus it needs shortened on one end by 1/4". I'm going to have it cut from 1/4" plate, then weld 2 strips of 1/4"x1" along the top edges only. It will have welds at the ends near the u-bolts, at the tube / center section end, and about an inch long tac at the top of the center section.

The tubes will be welded with 3- 1" welds around their intersection. I've read that doing a continuous weld around it could end up cracking due to the two different types of metal.

 

[tarry99]

Here is my plan. This is just the template and still needs some tweaking. I might flatten off the top and he cut the AMC insignia's backwards, plus it needs shortened on one end by 1/4". I'm going to have it cut from 1/4" plate, then weld 2 strips of 1/4"x1" along the top edges only. It will have welds at the ends near the u-bolts, at the tube / center section end, and about an inch long tac at the top of the center section.

The tubes will be welded with 3- 1" welds around their intersection. I've read that doing a continuous weld around it could end up cracking due to the two different types of metal.

First off the Nodular Iron housing and the mild steel tubes will weld OK as long as you pre-heat and use a high nickel rod or stainless like a 309 or 312........On the housing truss and the tubes both being mild steel I would be more inclined to stitch weld from side to side simply from the standpoint of not creating too much heat at any one spot......which will result in a bending......

Any Professional welder will stress the need to pre-heat and cool down slowly to avoid cracks and bending of the heated parts which would mean if it was in his shop the rear end would be clean, empty and on his bench.

 

[Swoop]

Nice template is the bell housing Notched yet if so please send me a paper template. I was just going to start with some cardboard. I think the Mig with the stitch welds would be best less heat. What amp would you run your mig at

 

[Swoop]

Didn't see the other post sorry I have access to a Miller 210 And a lincoln 375 Stick welder I work on base So have access to all the tools I need I just thought the meg welder would create Less heat I'll ask if we have any of those rods For the stick welder

 

[PaRenegade]

First off the Nodular Iron housing and the mild steel tubes will weld OK as long as you pre-heat and use a high nickel rod or stainless like a 309 or 312........On the housing truss and the tubes both being mild steel I would be more inclined to stitch weld from side to side simply from the standpoint of not creating too much heat at any one spot......which will result in a bending......

Any Professional welder will stress the need to pre-heat and cool down slowly to avoid cracks and bending of the heated parts which would mean if it was in his shop the rear end would be clean, empty and on his bench.

Agreed. This is why I'm taking it to a professional welder. Even though I have the tools, it's the skill that's needed. My comment on the cracking was solely about a continuous weld around the circumference vs the 3 one inch welds at third points.

Swoop - That's how I started it. First with a cardboard template, then I gave that to a friend who has a plasma table and he cut out the metal template on 18ga.
You said "bell housing" but I think you were referring to the center section / pumkin, and yes it's cut out around that. It goes up against the backside of the 2 webs at either side, but only welded on top.

 

[Swoop]

Ya that is what I ment. The welder here on base said he would weld it for me if I got it all ready. Ill get some pic on here as soon as I can thanks